Fix native Python callbacks after refactoring.

README.md

@@ -9,8 +9,8 @@ as frontends to scripts.
 ScriptForm takes a JSON file which contains form definitions. It then
 constructs web forms from this JSON and serves these to users. The user can
 select a form and fill it out. When the user submits the form, it is validated
-and the associated script is called. Data entered in the form is passed to the
-script through the environment.
+and the associated script or Python callback is called. Data entered in the
+form is passed to the script through the environment.
 
 ### Features
 
@@ -22,6 +22,8 @@ script through the environment.
 - Uploaded files are automatically saved to temporary files, which are passed
   on to the callback.
 - Multiple forms in a single JSON definition file.
+- Handles script / exception errors, HTML output or lets scripts and Python
+  callbacks stream their own HTTP response to the browser.
 
 ### Use-cases
 
@@ -106,9 +108,7 @@ ScriptForm requires:
 
 ## Usage
 
-### Authentication
-
-Passwords are stored in plain text.
+FIXME
 
 ## License
 

examples/native/native.json

@@ -22,6 +22,22 @@
                 }
             ]
         },
+        "export": {
+            "title": "Export data",
+            "description": "Export a dump of the database",
+            "submit_title": "Export",
+            "fields": [
+                {
+                    "name": "source_db",
+                    "title": "Database to export",
+                    "type": "select",
+                    "options": [
+                        ["devtest", "Dev Test db"],
+                        ["prodtest", "Prod Test db"]
+                    ]
+                }
+            ]
+        },
         "add_user": {
             "title": "Add user",
             "description": "Add a user to the htaccess file or change their password",

examples/native/native.py

@@ -1,20 +1,37 @@
 #!/usr/bin/python
 
 import scriptform
+import sys
 
-def job_import(values):
+def job_import(values, request):
     return "Importing into database '{}'".format(values['target_db'])
 
-def job_add_user(values):
+def job_export(values, request):
+    size = 4096 * 10000
+    request.wfile.write('HTTP/1.0 200 Ok\n')
+    request.wfile.write('Content-Type: application/octet-stream\n')
+    request.wfile.write('Content-Disposition: attachment; filename="large_file.dat"\n')
+    request.wfile.write('Content-Length: {0}\n\n'.format(size))
+
+    f = file('/dev/urandom', 'r')
+    sent_size = 0
+    while True:
+        buf = f.read(4096)
+        if sent_size >= size:
+            break
+        request.wfile.write(buf)
+        sent_size += 4096
+
+def job_add_user(values, request):
     username = values['username']
     password1 = values['password1']
     password2 = values['password2']
 
     if not password1:
-        return "Empty password specified."
+        raise Exception("Empty password specified")
 
     if password1 != password2:
-        return "Passwords do not match."
+        raise Exception("Passwords do not match.")
 
     # We do some stuff here.
 
@@ -23,7 +40,8 @@ def job_add_user(values):
 if __name__ == "__main__":
     callbacks = {
         'import': job_import,
+        'export': job_export,
         'add_user': job_add_user
     }
     sf = scriptform.ScriptForm('native.json', callbacks)
-    sf.run(listen_port=8080)
+    sf.run(listen_port=8000)

src/scriptform.py

@@ -6,6 +6,7 @@
 #  - Default values for input fields.
 #  - If there are errors in the form, its values are empties.
 #  - Send responses using self.send_ if possible
+#  - Complain about no registered callback on startup instead of serving.
 
 import sys
 import optparse
@@ -214,8 +215,8 @@ class FormConfig:
                 if not stat.S_IXUSR & os.stat(form_def.script)[stat.ST_MODE]:
                     raise ScriptFormError("{0} is not executable".format(form_def.script))
             else:
-                if not form_name in self.callbacks:
-                    raise ScriptFormError("No script or callback registered for '{0}'".format(form_name))
+                if not form_def.name in self.callbacks:
+                    raise ScriptFormError("No script or callback registered for '{0}'".format(form_def.name))
 
     def get_form(self, form_name):
         for form_def in self.forms:
@@ -224,12 +225,12 @@ class FormConfig:
         else:
             raise ValueError("No such form: {0}".format(form_name))
 
-    def callback(self, form_name, form_values, output_fh=None):
+    def callback(self, form_name, form_values, request):
         form = self.get_form(form_name)
         if form.script:
-            return self.callback_script(form, form_values, output_fh)
+            return self.callback_script(form, form_values, request.wfile)
         else:
-            return self.callback_python(form, form_values, output_fh)
+            return self.callback_python(form, form_values, request)
 
     def callback_script(self, form, form_values, output_fh=None):
         # Pass form values to the script through the environment as strings.
@@ -253,8 +254,26 @@ class FormConfig:
                 'exitcode': p.returncode
             }
 
-    def callback_python(self, form, form_values, output_fh=None):
+    def callback_python(self, form, form_values, request):
+        callback = self.callbacks[form.name]
+
+        try:
+            result = callback(form_values, request)
+            if result:
+                return {
+                    'stdout': result,
+                    'stderr': '',
+                    'exitcode': 0
+                }
+            else:
+                # Raw output
                 pass
+        except Exception,e :
+            return {
+                'stdout': '',
+                'stderr': str(e),
+                'exitcode': 1
+            }
 
 
 class FormDefinition:
@@ -744,7 +763,7 @@ class ScriptFormWebApp(WebAppHandler):
             # in some nice HTML. If no result is returned, the output was raw
             # and the callback should have written its own response to the
             # self.wfile filehandle.
-            result = form_config.callback(form_name, form_values, self.wfile)
+            result = form_config.callback(form_name, form_values, self)
             if result:
                 if result['exitcode'] != 0:
                     msg = '<span class="error">{0}</span>'.format(cgi.escape(result['stderr']))